Influence of titanium nanoparticles on cytotoxicity and inflammatory cytokines expression in gingival fibroblasts - An in vitro study [version 1; peer review: awaiting peer review]

Background Despite the success of titanium (Ti) implants in dental rehabilitation, emerging evidence implicates the release of titanium oxide nanoparticles (TiO 2NPs) from the implant surface as a potential contributor to the initiation of the pathogenic process leading to peri-implantitis and ultimately failure of the implants. However, a comprehensive investigation to elucidate the dose-dependent effects of TiO 2NPs on cytotoxicity and inflammatory responses is lacking. The present study was undertaken to evaluate the effect of different concentrations of TiO 2NPs on the cytotoxicity and inflammatory cytokine expression in Human Gingival Fibroblasts (HGFs). Methods HGFs were isolated from gingival tissue samples obtained from periodontally and systemically healthy subjects. Ti standard solution for ICP was diluted to create concentrations of (0.001 ppm, 0.01 ppm, 0.1 ppm, 1 ppm, 10 ppm, and 100 ppm) for cell culture media containing titanium. HGFs were then cultured in these varying concentrations for specific time periods (days 1, 3, 5, and 7) to assess cell viability. A cytotoxicity assay was performed to determine the levels and expression of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) and anti-inflammatory cytokines (IL-10, IL-12, TGF-β) using qRT-PCR and ELISA techniques. Results Our findings demonstrate a concentration and duration-dependent decrease in HGF viability upon exposure to titanium nanoparticles. Notably, a 50% reduction in cell viability was observed at the highest concentration (100 ppm). qRT-PCR analysis revealed a significant upregulation of pro-inflammatory cytokines, particularly IL-1β and IL-6, in HGFs exposed to titanium. Interestingly, the expression of anti-inflammatory cytokines (IL-10, IL-12, and TGF-β) remained comparable or even equivalent compared to controls across different titanium concentrations. Conclusions The study revealed a concentration and duration-dependent influence on HGF viability and cytokine profile, suggesting potential cytotoxicity and modulation of the inflammatory response mediated by TiO 2NPs. Further research is necessary to elucidate the underlying mechanisms and their implications for dental implant biocompatibility.